我更改了它，因此采用了绝对路径，例如

I changed the it so an absolute path is taken e.g.

File f = new File("C:\\data\\" + fileName);

这有效.在Servlet中使用它是否会更改它，以便需要绝对路径并使相对路径不可用?我测试了servlet外部的下载部分，它可以使用相对路径，或者如果未指定任何内容，则可以下载到项目文件夹中.

This works. Does having it in a servlet change it so an absolute path is needed and render relative paths unusable? I tested the downloading part outside of a servlet and it works with relative paths or it just downloads into project folder if nothing is specified.